THE POISON GARDEN website

Pontifications on Poison

Being some ramblings on events associated with poisonous plants.

Friday 22nd March 2013

I wonder when something becomes known rather
than news. I say this because of the publication of a review1 of
the diagnostic approach to and management of aristolochic acid
nephropathy (AAN) looking at what has been learned about dealing
with the condition in the twenty years since it became known.

Of course, it isn’t and if you go to the plant
page for
Aristolochia clematitis, birthwort, you’ll see that
I’ve written extensively about the condition and blogged about
it a number of times.

Nonetheless, this review article, whose
abstract begins ‘It has been 20 years…’ is being reported,
at least in the headlines, as if it were a new discovery.

FrenchTribune.com’s headline ‘Herbal Medicine
May Cause Kidney Failure’2 manages to both suggest this is a new
discovery and that there may still be doubt about the effect of
aristolochic acid (AA) though the piece itself makes it clear
that there is two decades worth of work to draw on showing that
AA does cause kidney failure.

Voice of America’s ‘Herbal Medicines Linked to
Kidney Disease’3 might lead the reader to assume this is a new
finding and the piece itself doesn’t help. Though the first
paragraph refers to ‘previous studies’ the second describes the
review as ‘research’ and calls it ‘a wake-up call’ as though
nothing had been done about the risks, to date. There is no
mention of the FDA’s warning against use of any remedy
containing AA that was issued in 2001.

Health.india.com asks ‘Could herbal medicines
cause kidney failure?’4 as if there is doubt in the matter and
its first paragraph refers to ‘the news that these ‘natural
remedies’ may be causing more harm than good is quite alarming’.
The FDA warning is mentioned but without giving a date so that
it seems to be something that has just happened. After that poor
start, the piece does go on to interview a pharmacologist who
details the situation well.

The Times of India avoids introducing doubt by
headlining its report ‘Herbal medicines causing kidney failure,
bladder cancer in India’5 but then goes
a little too far the other way by
stating ‘Herbal medicines are causing millions in India to
develop kidney failure and bladder cancer’.
The National Kidney
Foundation, India says kidney diseases ‘rank 3rd amongst
life-threatening diseases’ and have a prevalence of 100/million
of the population. That suggests around 1.2 million sufferers
but the NKF also says 22.5% of those require dialysis pointing
out the difference between kidney disease and kidney failure.
There are 200,000 deaths each year and around 90,000
transplants.

The danger of over-stating a serious problem is
that it tends to cause disbelief. Some years ago, a UK charity
claimed that child abuse affected almost half of all children.
When pressed, however, it turned out that its definition of
‘abuse’ was cast so wide as to include a sharp telling off from
a parent. The result of that overstatement was that many people
assumed child abuse was not a problem after all. The same could
happen if people think the figures for AAN are unreliable. There
is a big difference in perception between 'millions' and 'just
over a million'.

Medscape News is the only report I’ve seen that
gets to the core of the problem. Its headline, ‘Chinese Herb
Remains Health Threat Despite Widespread Bans’6 makes it clear
that AAN is not a new discovery and that action has been taken
to try and control the availability of AA.

The largest problem now is getting the message
through to those in Taiwan and China who think that the campaign
against products containing AA is just another example of
western medicine not understanding. In that situation, speaking
of ‘could’ or ‘may’ provides a get out.

I know good science is always doubtful and
hesitates to make over dogmatic pronouncements because something
else may be discovered tomorrow. But, though this justifies
saying that taking products containing AA ‘may’ result in kidney
disease, that is not the same thing as saying that AA may cause
kidney disease. The science is strong enough to say that AA does
cause kidney disease and bladder cancer in the same way that you
can say smoking does cause lung diseases.